The invention relates to photoactive pyrite layers, processes for their preparation, and the use of such pyrite layers.
The semiconductors heretofore principally used for solar cells are silicon, cadmium sulfide, gallium arsenide, copper-indium selenide, and indium phosphide. Semiconductors made from silicon were developed over three decades ago. However, it is known that the costs of making solar cells are still too high for wide commercialization. For single-crystal and polycrystalline silicon, the high requirements in terms of purity of the material and the energy consumption for their preparation are the most important cost factors. For amorphous silicon, adequate stability of the material is not yet assured, so that its use for solar cells has thus far been justified only in special cases.
The other solar cell materials which have been developed intensively are, as a rule, even more expensive than silicon (e.g. GaAs, InP), or they contain less common and toxic elements (e.g. cadmium in cadmium sulfide).
At present it cannot yet be forseen which semiconductor material will prove industrially successful. The development of silicon is generally assigned a high degree of importance. Also, most research work is concerned with this material for solar cells and optoelectronic components. However, for a broad, economical use of silicon as a solar cell material, the costs of preparation must be capable of reduction at least to 10% of present costs.
The fundamental possibility of using pyrite as a solar cell material is known from the Journal of Applied Electrochemistry, 13, 743-750 (1983). However, the detailed knowledge required cannot be gleaned from this source.